Polarplot all positive values of the angle theta

Hello, i'm trying to get my plot to look like this:

It currently looks like this:

Here is my Code for the plot above:

theta = linspace(-pi,pi,1000);
theta_deg = rad2deg(theta);

EF = cos(theta);
y = polarplot(theta,10*log10(EF),'linewidth',3);

title('E Field (dB)');
legend('\theta = \pi/4');
set(gca,'fontsize',12);
ax = ancestor(y,'polaraxes');
ax.ThetaZeroLocation = 'top';
ax.ThetaDir = 'clockwise';
ax.ThetaLim = [-180 180];
rlim([-40 0])

Answer 1

[Simon Chan]

Workaround by modifying the TickLabel as follows:

theta = linspace(-pi,pi,1000);
theta_deg = rad2deg(theta);
EF = cos(theta);
y = polarplot(theta,real(10*log10(EF)),'linewidth',3);      % Plot the real part only, prevent warning pop-up
title('E Field (dB)');
legend('\theta = \pi/4');
set(gca,'fontsize',12);
ax = ancestor(y,'polaraxes');
ax.ThetaZeroLocation = 'top';
ax.ThetaDir = 'clockwise';
ax.ThetaLim = [-180 180];
rlim([-40 0]);
ax.ThetaTickLabel = string(abs(ax.ThetaTick));              %% <-- Add this line